Author Topic: Adjustable Loops  (Read 51151 times)

xarax

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Re: Load testing of various Bowline structures
« Reply #60 on: June 10, 2015, 12:01:30 PM »
There are two senses here : that of the proportion to the tensile strength; and that in proportion to manual strength.

   True. I was talking about the first, which does not depend on the size of the rope.
   However, obviously a knot tied on a rope of a larger size, can be more easily untied than the same knot, tied on a smaller size, even if both are loaded by the same percentage of its MBS - simply because the size of human fingers, and their strength, does not vary so much  :). So, let us examine/define the easiness of untiability of a knot when it is tied on ropes of some standard sizes, say, 1/2, 3/8 and 1/4 inch.
« Last Edit: June 12, 2015, 10:56:43 AM by xarax »
This is not a knot.

xarax

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Re: Load testing of various Bowline structures
« Reply #61 on: June 11, 2015, 02:18:31 AM »
"*<this_material> so knotted*".

 "*<this_knot> thus materialized / embodied*".
This is not a knot.

Dan_Lehman

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Re: Load testing of various Bowline structures
« Reply #62 on: June 11, 2015, 07:24:08 AM »
"*<this_material> so knotted*".

 "*<this_knot> thus materialized / embodied*".

 :D

But I think I'll have a much easier time describing
"<this_material>" than your side of that bargain!   ::)

(Though, I had mused about your take on it and seeing
*knots* modeled as biological entities and then asking
Where can they *live*? as a measure of media!?
Can the OzM_knot *live* in nylon mono. fishline?)

 :)


Dan_Lehman

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Re: Bowline "knot wars"
« Reply #63 on: June 11, 2015, 08:36:45 AM »
I am not invited to give suggestions (and really there is not any reason for it, I am only passive observer). But, I should like to include Double Bight Bowline (= Prohaska bwl = Janus bwl, one variant) in the "war".
Thx, regards
ZZ
One thing that might be worth doing --depending upon
the test apparatus, evaluation-- is making this knot
(what I called "Janus" for the like *faces* in opposite
directions) a quadruple-bight one --i.e., in the spirit
of "one good turn deserves another" but more to the
point of questioning if more diameters through the
turNip begets strength, take the tail back'n'forth
one more time, stuffing 5 diameters.  NOT that this
would be a practical knot, but simply to answer the
question about a more gradual curvature giving greater
strength.  BUT, in your testing, would we be able to
have confidence in a (single?) result?


--dl*
====

xarax

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Re: Load testing of various Bowline structures
« Reply #64 on: June 11, 2015, 10:31:43 AM »
Where can they *live* ?

  I had searched for the proper verbs, among many synonyms - and I had chosen those two ( "embodied" / materialized" ), because I had found that they are used more often than the others to denote incarnations of ( Platonic ) ideas.
  What is a wheel ? An embodied / materialized circumference of the circle - a mathematical idea, which "exists" even in a completely annihilated world without any matter left !  :)   
This is not a knot.

Dan_Lehman

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Re: Load testing of various Bowline structures
« Reply #65 on: June 11, 2015, 07:20:42 PM »
Where can they *live* ?

  I had searched for the proper verbs, among many synonyms - and I had chosen those two ( "embodied" / materialized" ), because I had found that they are used more often than the others to denote incarnations of ( Platonic ) ideas.
  What is a wheel ? An embodied / materialized circumference of the circle - a mathematical idea, which "exists" even in a completely annihilated world without any matter left !  :)   
In at least Ada programming language, the term used
for making some particulars of a "generic" subprogram
is "instantiation".

Now, a wheel vs. circle I think stands at an easy-to-figure
remove from instantiations of "*knot*", as both of the
former are round --just a question of simple imperfection
of the material thing; but re *knot*, the geometry of it
--its angles and so on (even not looking to further material
aspects of compression)-- are not so well specified by any
ideal, for the ideal doesn't consider what is though essential
for *knot* (yes?  no?) : force & tension.  (Or one has
some infinity of those ideals to match whatever turns up,
and this sort of thinking gets one nowhere, IMO!

(E.g., does The Bowline (ideal) have a turNip that contains
<what degree ...?> deflection of the S.Part & eye leg?
(esp. if SS'd  :D ).  A real one might start out that way,
and through loading, come to actually has ever so slight
a gap at this point, wanting to open the helix.)


--dl*
====

xarax

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Re: Load testing of various Bowline structures
« Reply #66 on: June 11, 2015, 09:03:41 PM »
the ideal doesn't consider what is though essential for *knot*  : force & tension

In the the "Ideal" knots I am talking about, there are no "forces" or "tensions" : the knots shrink only because their ropelength is minimized. This pure geometrical condition is enough to force them become as compact as possible ( without any compression of the "body" or change of the circular cross section of the rope ). 

does The Bowline (ideal) have a turNip that contains <what degree ...?> deflection of the S.Part & eye leg?
   Unfortunately, mathematicians have not calculated/simulated our "open" knots in their computers. For "closed" knots and links, they have made much progress. See :
   http://www.jasoncantarella.com/wordpress/software/ridgerunner/
« Last Edit: June 11, 2015, 09:10:05 PM by xarax »
This is not a knot.

Mobius

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Re: Load testing of various Bowline structures
« Reply #67 on: June 12, 2015, 09:50:54 AM »
Hi all,

Please don't forget to give me images (or links to images) for the knots you would like me to trial. I am a 'visual' learner, so the more you can give me to see, the better. As a new knot tyer, it doesn't take much to give me tying problems. Expanded views really help, along with advice on particular issues/preferences with regard to dressing the knot prior to load.

If I am not confident I know exactly how a knot you propose is tied and dressed properly, then potentially the trialling of my circumspect version of 'your knot' is a waste of time.

I am going to spend some time shortly and go through this thread and list the knots I feel comfortable tying properly. If the knot you proposed isn't on that list, you can probably guess why ;)

Help me out out much as possible please.

Cheers,

mobius


Mobius

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Re: Bowline "knot wars"
« Reply #68 on: June 13, 2015, 08:49:01 AM »
One thing that might be worth doing --depending upon the test apparatus, evaluation-- is making this knot
(what I called "Janus" for the like *faces* in opposite directions) a quadruple-bight one --i.e., in the spirit of "one good turn deserves another" but more to the point of questioning if more diameters through the
turNip begets strength, take the tail back'n'forth one more time, stuffing 5 diameters

I did not set out to make the exploding loop (shown below) with 5 diameters (Image 2), however it ended up that way after what I suspect might be the best dressing for the knot. An exploding loop is not a bowline, or can it be? The knot shown below certainly has a turNip and the tail does form a bight held in place by the turNip. I cannot say I am comfortable calling the knot I show a bowline though.

Quote
NOT that this would be a practical knot, but simply to answer the question about a more gradual curvature giving greater strength.  BUT, in your testing, would we be able to have confidence in a (single?) result?

--dl*
====

As a exploding loop this one might be practical. I find it easy to tie, untie after load and it appears secure after a preliminary trial. The images below show the knot did not collapse under load and the tail bight appeared to remain intact and in place. Some of these "L shaped" knots fold in half under load, this one does not. Image 3 is the knot I trialled prior to load and Image 4 is the same knot after a load of 130kg. Image 4 shows some compression of the nub, however all knots change somewhat under load and the nub geometry is still recognisable.

The knot fulfills some of the 'acronym soup' stuff as well: It is PET (post eye tiable) and TIB (tiable in the bight).

Another version of this knot, after a simple dressing change, has a 3 diameter turNip. It is a simpler looking knot, however I have not trialled this version yet.

Cheers,

mobius

Edit: Link also also shows the 3 diameter version

Link: https://docs.google.com/presentation/d/1VuospIgtPj5aG2DJIDFQGEHC0TWEYMrz8GSjaJlbPSg/edit?usp=sharing

« Last Edit: June 13, 2015, 10:27:24 AM by mobius »

Dan_Lehman

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Re: Bowline "knot wars"
« Reply #69 on: June 14, 2015, 06:12:37 AM »
One thing that might be worth doing --depending upon the test apparatus, evaluation-- is making this knot
(what I called "Janus" for the like *faces* in opposite directions) a quadruple-bight one --i.e., in the spirit of "one good turn deserves another" but more to the point of questioning if more diameters through the
turNip begets strength, take the tail back'n'forth one more time, stuffing 5 diameters

I did not set out to make the exploding loop (shown below) with 5 diameters (Image 2),
...
I hope that you don't feel obligated to find a practical
reason for the knot tested : again, my point was to test
the theory about gradual turns, and so adding diameters
to a common practical knot, which addition should largely
preserve the character of the knot but just vary it by giving
those extra diameters, serves this purpose best, IMO.
--rather than finding some basis for another knot and
then it would be a debatable matter whether any observed
difference was attributable to the diameters alone or to
some other different aspect!

In a similar tact, it might make sense to test a knot that
has been unusually hard set by some device --i.e., in a way
impractical--, so as to achieve a state that might shed some
light on knot workings.  (And consider that fishing knots
are usually given prescribed settings that would require
such special devices to be effected in "rope", in forces
equivalent for rope!)  And it's not that I'd expect the
result of some such testing to be "Thou shalt forever
use the SS-SuperSnugger-Model-108 on thine knots",
but insight that such conditions matter.  (At present,
we have the issue about setting a fig.8 that is
oriented with S.Part going to the far end, bearing
into its twin part vs. pulling away from it (what its
twin would were it so loaded), being set by loading
the tail --that twin part-- so as to make it unable
to be simply pushed aside, without consuming much
force from the S.Part, and maybe that offloading
makes for added strength?!  Now, in this case, I would
hope that such setting was practical, doable with manual
force.)


--dl*
====

Mobius

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Re: Bowline "knot wars"
« Reply #70 on: June 14, 2015, 07:21:37 AM »
One thing that might be worth doing --depending upon the test apparatus, evaluation-- is making this knot
(what I called "Janus" for the like *faces* in opposite directions) a quadruple-bight one --i.e., in the spirit of "one good turn deserves another" but more to the point of questioning if more diameters through the
turNip begets strength, take the tail back'n'forth one more time, stuffing 5 diameters

I did not set out to make the exploding loop (shown below) with 5 diameters (Image 2),
...
I hope that you don't feel obligated to find a practical
reason for the knot tested : again, my point was to test
the theory about gradual turns, and so adding diameters
to a common practical knot, which addition should largely
preserve the character of the knot but just vary it by giving
those extra diameters,
serves this purpose best, IMO.
--rather than finding some basis for another knot and
then it would be a debatable matter whether any observed
difference was attributable to the diameters alone or to
some other different aspect!

--dl*
====

I felt no obligation, I just happened to be playing around with 'L shaped' exploding loops and with this particular knot I thought "5 diameters, that's interesting" and remembered your comment :)

I understand that we do not particularly need 4, 5 etc... diameter turNips. The knot I showed just happened to have a large one when I dressed it a certain way (probably the best way after more reflection on it). As it turns out, it would be easy to test a 4 diameter and a 3 diameter, devolved version, of the 5 diameter exploding one I show, simply by untucking the tail. The knot's character would be preserved I think, have a look at it yourself and see if you agree.

The devolved  3 diameter case isn't exactly secure, however I suspect it would hold well enough for a trial, if I treated it carefully.

Cheers,

mobius

Luca

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Re: Load testing of various Bowline structures
« Reply #71 on: June 14, 2015, 03:48:56 PM »
Hi xarax,

A very good, simple, secure, well balanced adjustable loop. The L-shape "handle" is perfect, almost 90 degrees.

This loop is based on the same principles as the Pretzel loop and the Clove X loop :

By your description I think that you,in the first image posted by Alan at reply #56, maybe saw the loop in the image below(sorry for my beloved dirty old rope..) .In fact the image of the finished knot may be a bit ambiguous with regard of how it is built,but Alan edited his post( http://igkt.net/sm/index.php?topic=5383.msg36083#msg36083 )with new images showing that the knot is actually a fixed loop with a collar structure.

                                                                                                                                   Bye!



xarax

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Re: Load testing of various Bowline structures
« Reply #72 on: June 14, 2015, 04:19:50 PM »
   In a way, Alan Lee "stabilized" the Girth hitch-based adjustable loop, as I had stabilized the Clove-hitch based one...
   When I had tied and tried those loops (1), I was looking for a TIB knot -(*) that is probably why I had missed them then...

  1. http://igkt.net/sm/index.php?topic=4347.0
  2. http://igkt.net/sm/index.php?topic=5357.msg36146#msg36146

(*)  Oh, my KnotGod ! This IS TIB - although its Standing Part before the eye is not ( so, it is not PET ). Thank you Luca !
      So, I should had said " I was looking for a PET and TIB knot...".
      The somehow-adjustable loop, based on a fig.8 knot tied on the Standing Part before the eye shown at (2), is also not-PEt, but TIB.
      Now, I do not remember any more which knot I saw !  :)  I wrote that Alan s Lee loop was not TIB, so, even if I had seen another knot, most probably I had NOT seen the knot you show ! You can pass the Standing Part s first curve "over" or "under" the first segment of the nub it meets. The two knots are, regarding their general shape, their nipping / gripping power and their mid-air stability, pretty much the came - however, only the one turns into a TIB knot ( which its the one you probably show - we will be sure, the moment you remove the dirt from this rope ! ) I do not know if Alan Lee has tied or shown the TIB variation - you should clarify this matter with him. For me, and for the time being, this TIB adjustable loop is called Luca s TIB adjustable loop, I am afraid...

P.S. I had thought that the adjustable loop Luca had shown was the TIB one he shows in his next post - the dirt on the ropes, and the out-of-focus picture, and my poor sight, all contributed in the tying of this knot, but the primum movens of the whole sequence of things was Luca himself.
« Last Edit: June 15, 2015, 09:46:49 AM by xarax »
This is not a knot.

Luca

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Re: Load testing of various Bowline structures
« Reply #73 on: June 14, 2015, 10:23:17 PM »
And I am afraid that the so-called "Luca s TIB adjustable loop" shown above is not TIB...  :( the first curve of the standing part pass "under all" in the image above(and yes,is not so clear,but at the moment I have available only the beloved dirty old rope);once removed the tail from the knot's nub,remains a Fig. 9 equivalent tied on the standing part.
So,now I am curious of the "Xarax TIB adjustable loop"...

Luca

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Re: Load testing of various Bowline structures
« Reply #74 on: June 15, 2015, 01:56:59 AM »

I have thought that the TIB variation of the so-called "Luca s TIB adjustable loop" was the one(not so stable) shown below(first pic;in the second pic I have capsized the knot in the fashion of the loop that you have shown):


« Last Edit: June 16, 2015, 04:11:25 AM by Luca »